I know exactly what you're going through, my parents divorced when i was 6 so i was still very young and didnt really understand untill i was older. Looking back i realise there was nothing i could of done, the best thing you do is tell them how much is upsets
YOU and how its affecting
YOUR life, not theres. Once they realise its not just the two of them involved, they will start listening. My parents splitting up upset me alot and i miss my dad because i never really see him, but i know it was the best thing to do.
Sit them both down and explain, if they dont listen, go and stay with a friend/family member and tell them gently that you wont put up with it.
Hope you work it out